The optimum amount of water use and nitrogen fertilizer in the peanut (Arachis hypogaea L.) With the aim of achieving net profit

ABSTRACT: To calculate the optimum amounts of consumed water and nitrogen fertilizer on peanut with the aim of maximum benefit gain, an examination on frequented plots was performed in randomized complete block design with 3 replications in northern Iran in 2009. In this experiment, controlled conditions and irrigation with 6, 12 and 18 days turns were selected as major treatment and various levels of nitrogen fertilizer with 0,30,60,90 (khan/ha) were selected as minor treatment. In present study, production functions such as amounts of consuming water and nitrogen fertilizer with water consumption efficacy based on biologic function, pod and Grain function were calculated based on mathematical and economical analysis. Results rates of cost, income and net benefit indicated that total cost in 6 days irrigation period (with 3280 m2 consumed water) didn’t display significant increase compared to 12 days irrigation (with 3000 m2 consumed water) and 18 days irrigation interval (with 2640 m2 consumed water). But income rate resulted from 6 days irrigation management compared to 12 and 18 days irrigation intervals indicated 55.3% and 64.8% increase, respectively. Net benefit rates in 6, 12, 18 days irrigation turn were 637.37, 336.88, 306.81 Dollars, respectively. Out of these, contribution of 6 days irrigation management was higher compared to other treatments. According to the paid expenses in 3 stages including plantation, preservation and harvesting, and considering the costs of water and fertilizer , net benefit increased with decreased irrigation turn . But using greater amount of nitrogen fertilizer by 90 (kg/ha) increased the costs and also decreased the net benefit. With decreased fertilizer usage by 60 kg fertilizer per hectare, income and net benefit were 647.05 and 447.66 Dollars, respectively and saving in fertilizer usage increase the net benefit by 18.33 Dollars. In general, results indicated that net benefit consistent to consumed water has a linear ascending trend. On the other hand, income per surface unit increasing with water consumption increasing. Maximum income was proportional to maximum operation. But in various levels of nitrogen fertilizer consumption, firstly amount was related to ascending trend but subsequently it had a descending trend. Then it is perceived that consuming nitrogen fertilizer in greater amount than plant needs couldnʹt raise the net income. Thus the best treatment to achieve maximum net income is 6 days irrigation turn and 60 kg nitrogen/hectare with 1085.04 Dollars value.